Acid-catalyzed reactions of naphthalene



United States Patent 3,311,669 ACID-CATALYZED REACTIONS OF NAPHTHALENE Ronald D. Bushick, Glen Mills, Pa., assignor to Sun Oil Company, Philadelphia, Pa., a corporation of New Eerse N0 l rawing. Filed July 11, 1966, Ser. No. 564,713

8 Claims. (Cl. 260-668) This invention relates to a hydrocarbon conversion process and it pertains more particularly to the reactions of naphthalene with parafiin hydrocarbons or benzene in the presence of a hydrogen fluoride and boron trifiuoride catalyst.

It is known that polycyclic aromatic hydrocarbons may effect an intermolecular condensation in the presence of hydrogen fluoride or hydrogen fluoride and boron trifluoride catalysts in the absence of mononuclear aromatic hydrocarbons. For example, the following reaction may be effected:

It is also known that an aromatic hydrocarbon such as benzene can be converted with a paraflin hydrocarbon such as normal pentane, hexane, heptane, etc., to alkylated aromatic compounds. United States Patent 2,430,516 teaches alkylating aromatic hydrocarbons with parafiin hydrocarbons, said alkylation being efiected in the presence of a hydrogen fluoride-boron trifluoride catalyst at a temperature within the approximate range of 180 to 400 F.

The present invention relates to a process for reacting naphthalene with normal parafiin hydrocarbons or benzene in the presence of a hydrogen fluoride-boron trifluoride catalyst at temperatures in the range of 0 to 70 C. When benzene is the reactant with naphthalene, a condensation reaction takes place accompanied by hydrogenation and dehydrogenation to produce substantial yields of 1-phenyl-3,4-dihydronaphthalene along with l-phenyl- 1,2,3,4-tetrahydronaphthalene and l-phenylnaphthalene.

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+ other reaction products tetrahydroanthraceue The conversion temperature of this reaction is important since only sufficiently low temperatures give the desired tetrahydroanthracene. The conversion may be effected at a temperature in the range of to 70 C. but

25 to 65 C. is the preferred range. The temperature should not be allowed to rise to 80 C. or above where cyclization does not occur.

4 mass is quenched in ice water resulting in the separation of an aqueous acid layer and an organic layer. If desired, the acid can be neutralized by adding Na CO the organic layer decanted and washed with water. Dilution When benzene is the reactant, the suitable temperature of the organic layer with a solvent such as pentane facilialso ranges from 0 to 70 C. but 5 to 45 C. is the pretates the decanting step. ferred range. The products of the reaction can be removed from the In either case the process is operated at a pressure organic layer in any convenient manner, as for example, sufficient to maintain substantial liquid phase conversion vacuum distillation or chromatographic techniques. conditions. In the process of this invention, the pro- The following examples illustrate the invention: portions of catalysts are important. The hydrogen fiuo- EXAMPLE I ride should be in molar excess over boron trifiuoride. Neither hydrogen fluoride nor boron trifluoride used alone The reaction Ve$ $e1 was a smfill reactor q p Wlth will give satisfactory results. Mole ratios of hydrogen a Shaker and h g f coohl'lg means- The reactor fluoride to boron trifiuoride in the range of 10:1 to 35:1 Was flushed out Wlth hltrQgeh- Heptahe h are preferred for maximum effectiveness. An amount of naphthalene p e h Char'ged Into the boron trifluoride ranging from a catalytic amount up feflcmf and Wcre sohchfied 115mg hquld nltfoghh- The to excess boron trifluoride to naphthalene is suitable but r a r Was evacuated and HF added. The reactor was mole ratios fr m 05:1 to 1;1 are preferred, agitated and heated to 50 C. where BF3 was added. The Reaction times for the process of from a few minutes BF pressure was sufiicient to maintain essentially all up to two hours are suitable. The range of 10 to 60 of the HF in liquid phase. The reactor was held at minutes is preferred. 50 C. for 60 minutes from the time of BF addition. The normal parafiins or benzene should be present in Shaking of the reactor was continued throughout the the reaction mixture in a molar excess over moles of reaction time. The vessel was then cooled to 15 C., naphthalene since at lower mole ratios, the intermolecuand the contents quenched in ice. The resulting two lar condensation reaction of Equation 1 competes with phases were neutralized with Na CO after which the the desired process. The upper limit of the mole ratio organic layer was drawn off and washed several times of normal paraffins or benzene to naphthalene is not with twice its volume of Water. The organic layer was critical. A preferred ratio lies in the range of 2:1 to analyzed by vapor phase chromatography with results 10:1. as given in the table, Run No. 1.

TABLE Run 1 Run 2 Run 3 Charge (moles):

Heptane 0. 10 0. 10 Benzene 0.23 Naphthalene. 0. 05 u, 05 0 05 HF 1.02 1. 04 1.11 BF; 0. 05 0.04 0.04 Reaction Time (minutes) 30 15 Reaction Temperature, C 5O 3O 30 Product Distribution (wt. percent):

Naphthalene 19. 6 33. 8 30. 2 THA1 14.0 8.3 5.5 PDHN 0. 9 1.8 20.1 PTHN 1.1 4.7 1.1 PN 5.5 4.6 5.6 Binaphthyls Remainder Remainder Remainder 1 THA: Tetrahydroanthracene; PDHN: 1-phenyl-3,-dihydronaphthalene; PTHN 1- phenyl-I,2,3,4-tetral1ydronaphthalene; PN=1-pheny1naphthalene.

2 The high-boiling fraction probably consisted of binaphthyls and partially hydrogenated binaphthyls. The following were shorm to be present by mass spectroscopy:

The reaction of this invention can be carried out in any convenient manner using conventional type equipment. For example, the naphthalene and paraffin or benzene are charged in to a closed reaction vessel equipped with heating and agitating means. The required amount of HP is then added and the mixture heated to the desired reaction temperature. The BF is added and the vessel shaken or the contents otherwise agitated in order to insure efiicient contact of the HF-BF catalyst with the mixture of starting materials. After adding the BE; the reaction mass is maintained at the desired reaction temperature for the desired contact time.

At the end of the reaction period the vessel is opened to effect the removal of most of the B1 (B.P.=10l C.) and much of the HF (B.P.=19.4 C.). Any remaining HF and any dissolved BF can be distilled from the vessel. If it is desired to remove the HF as a liquid rather than as a gas the reaction vessel is cooled to below 19.4 C. and opened to remove the BR. The reaction EXAMPLE II The procedure of Example I was repeated but with shorter reaction times and lower temperatures with results as given in the table, Run No. 2.

EXAMPLE III Benzene was reacted with naphthalene using the procedure of Example I with reaction conditions and results as given in Run 3 of the table.

The compounds produced by the process of this invention are known and their utility is well known in the art. For example, l-phenylnaphthalene, l-phenyl-3,4-dihydronaphthalene, and 1 phcnyl 1,2,3,4 tetrahydronaphthalene are useful in making dyes and tetrahydroanthracene is a useful precursor to polycarboxylic acids which are used to make polymers.

What is claimed is:

1. A process for producing tetrahydroanthracene which comprises contacting naphthalene with a molar excess of a normal parafiinic hydrocarbon over moles of naphthalene in the presence of a catalyst consisting essentially of hydrogen fluoride and boron trifluoride, at a conversion temperature between 0 and 70 C., under a pressure sufficently high to maintain substantially liquid phase conversion conditions.

2. A process according to claim 1 in Which the molar ratio of normal paratlinic hydrocarbon to naphthalene is between about 2:1 to about 1-0: 1.

3. A process according to claim 2 in Which the temper ature is in the range of 25 to 65 C.

4. A process according to claim 2 in which said normal parafiinic hydrocarbon is n-he tane.

5. A process according to claim 3 in which said normal parafiinic hydrocarbon is n-heptane.

6. A process for producing a condensation product comprising 1-phenyl-3,4-dihydronaphthalene which comprises contacting naphthalene With a molar excess of benzene, in the presence of a catalyst consisting essential- 1y of hydrogen fluoride and boron trifluoride, at a con version temperature between 0 and 70 C., under a pressure sutficiently high to maintain substantially liquid phase conversion conditions.

7. A process according to claim 6 in which the molar ratio of benzene to naphthalene is between 2:1 to about 10:1.

8. A process according to claim 7 in which the temperature is in the range of 5 to 45 C.

References Cited by the Examiner UNITED STATES PATENTS 2,430,516 11/1947 Lien et a1. 26067l 2,884,469 4/ 1959 McCaulay 2-60-671 3,244,758 4/1966 Eberhardt 260671 X DELBERT E. GANTZ, Primary Examiner.

C. R. DAVIS, Assistant Examiner. 

1. A PROCESS FOR PRODUCING TETRAHYDROANTHRACENE WHICH COMPRISES CONTACTING NAPHTHALENE WITH A MOLAR EXCESS OF A NORMAL PARAFFINIC HYDROCARBON OVER MOLES OF NAPHTHALENE IN THE PRESENCE OF A CATALYST CONSISTING ESSENTIALLY OF HYDROGEN FLUORIDE AND BORON TRIFLUORIDE, AT A CONVERSION TEMPERATURE BETWEEN 0 AND 70*C., UNDER A PRESSURE SUFFICIENTLY HIGH TO MAINTAIN SUBSTANTIALLY LIQUID PHASE CONVERSION CONDITIONS. 